Hong Kong, July 30 : Hong Kongs new police unit enforcing the national security law imposed in the city by China, arrested four student members of a pro-independence group, it was reported on Thursday. The arrests of the suspects, aged 16 to 21, on Wednesday marked the first such crackdown on anti-government activists not at the scene of street protests since the legislation came into effect on June 30, reports the South China Morning Post (SCMP) newspaper. Police did not reveal the suspects' identities, but images posted online showed Tony Chung, one of the former convenors of the group Studentlocalism, being taken away in handcuffs. Studentlocalism was a pro-independence group that was disbanded on June 30, hours before the Beijing-imposed national security law came into effect, banning acts of secession, subversion, terrorism, and collusion with a foreign country to endanger national security. In a late Wednesday night press conference, Senior Superintendent Steve Li of the National Security Department under the police force said the suspects' group had recently declared the establishment of a body to promote pro-independence political ideals "using any means possible" and build a "Republic of Hong Kong". Previous arrests under the national security law have been made at protests over slogan shouting and flag waving. Earlier this month, a 23-year-old man became the first person charged under the new national security law for allegedly riding into a group of policemen during a protest while carrying a flag calling for the liberation of Hong Kong. He was officially charged with one count of inciting secession and another of terrorism. /IANS